Comment: please research the rumor that levees in New Orleans were blown
up during Hurricane Katrina which occurred August 29, 2005. The 10th
anniversary is a few months away and the rumor still circulates.

Probably not so obvious after the water went rushing through the hole made by the explosive. However, the reports done by the Corp of Engineers found no evidence of deliberate damage and did find evidence of poor construction, design and maintenance. I don't have a cite at the moment but am instead going by memory from reading the newspapers in the year or so afterwards.

The 1927 flood was the largest ever recorded on the lower Mississippi Valley (Figure
4.6). The deluge was preceded by a record 18 inches of rain falling on New Orleans in a 48
hour period in late March 1927, which was followed by six months of flooding. The levees
that were supposed to protect the valley broke in 246 places, inundating 27,000 square miles
of bottom land; displacing 700,000 people, killing 1,000 more (246 in the New Orleans area),
and damaging or destroying 137,000 structures.
There was an enormous public outcry for the government to do something more
substantive about flood control. Fearing the worst, the political leadership of New Orleans
sought relief by dynamiting the Mississippi levee in Plaquemines Parish, downstream of New
Orleans. By the time promises were made regarding damage compensation and the necessary
permission was granted, the flood had crested and begun to subside. No less than seven
sequences of dynamiting ensued, all promoted by fear. The initial dynamiting of the
Caernarvon levee below New Orleans with 30 tons of dynamite devastated much of St.
Bernard and Plaquemines Parishes, and their residents were never remunerated in any
meaningful way for their damages. The saddest aspect of the dynamiting was that it was
unnecessary, as several levees gave way upstream of New Orleans, one the very afternoon of
the dynamiting, and the river level at New Orleans never regained its maximum crest during
the remainder of that record year (Barry, 1997)

When I lived in Greenville Mississippi, one of the apartments I lived in was inside the 1936 levees. This could have been very wet but it was actually built on top of the 1927 levee. I don't remember the author but he was famous, at least locally. He wrote of patrolling the levees during flood stages to watch for someone trying to dynamite the levee.